Carrageenan

Certain concentration of Carrageenan solution is injected into the hind paw of the rodents subcutaneously, 4 – 8 hours late, the pressure threshold of the injected paw is measured using Randall - Selitto clip and compared with the baseline (the pressure threshold before Carrageenan injection). The dropping of threshold indicates the hyperalgesia of the injected paw. Effective analgesics are able to reverse the dropping of threshold.